Funding is sought for a PE Biosystems Voyager DE PRO MALDI/TOF Mass Spectrometer. MALDI/TOF mass spectrometry is the method of choice for mass analysis of peptides, proteins, and polymers, molecules that are non-volatile and/or thermally unstable. The mass spectrometer will be located in the Analytical Instrumentation Facility of the Institute of Chemical Biology & Drug Discovery at Stony Brook. It will significantly enhance the research productivity of seven established research scientists from Stony Brook who comprise the major user group. The NIH-funded studies explore the structure-function relationships that control spectroscopic properties of protein biosensors, enzyme catalysis, formation of protein catalysts, protein folding, cancer therapy, ligand-mediated signal transduction, and glycosylation. MALDI/TOF is essential for these projects that require peptide synthesis, polymer synthesis, protein ligation, and glycopeptide mapping. Many of these samples are synthetically prepared. Mass spectral analyses are required to verify that the correct product has been obtained before proceeding with further experiments, and for analyzing side-reactions that may have occurred. Thus, same day availability is key to the success of our research enterprise. Other samples are difficult to ionize, and require method development. This method development requires a knowledge of the properties of the samples under investigation, an investment of time to find the best ionization conditions, and care to not waste limited amounts of samples. The instrument will be operated and maintained by trained personnel in the Institute of Chemical Biology & Drug Discovery Analytical Instrumentation Facility. The Director of the Facility will schedule daily operation and provide technical expertise for users. A Research Support Specialist will run samples for users who do not require "hands-on" analysis of their own samples. The Institute of Chemical Biology & Drug Discovery steering committee will oversee administration of the instrument, ensure access to major users and other NIH-funded investigators, and manage long term operation of the instrument. The Stony Brook administration and the Institute of Chemical Biology & Drug Discovery have made a significant contribution toward the maintenance and operation of the instrument. [unreadable] [unreadable]